WO2007013515A1

WO2007013515A1 - Gas discharge light emitting panel

Info

Publication number: WO2007013515A1
Application number: PCT/JP2006/314780
Authority: WO
Inventors: Takehiro Zukawa; Seigo Shiraishi; Kojiro Okuyama; Junichi Hibino; Keiji Horikawa
Original assignee: Matsushita Electric Industrial Co., Ltd.
Priority date: 2005-07-27
Filing date: 2006-07-26
Publication date: 2007-02-01
Also published as: KR20080030045A; US20100156266A1; JPWO2007013515A1; CN101233596A

Abstract

A gas discharge light emitting panel wherein deterioration of display characteristics of a panel due to fluctuation of light emitting characteristics of a fluorescent material is suppressed. The gas discharge light emitting panel is provided with a front plate and a rear plate arranged to face through a discharge space, and a fluorescent layer which is arranged on a main plane on a discharge space side of the rear plate and emits light by ultraviolet generated in the discharge space. The fluorescent layer is a panel which includes first and second fluorescent materials of which directions of fluctuation of one characteristic selected from luminance and chromaticity due to driving of the panel are opposite.

Description

Specification

Gas discharge light emitting panel

Technical field

The present invention relates to a gas discharge light-emitting panel that is an image display device that utilizes light emission of a phosphor by ultraviolet rays generated by gas discharge.

Background art

In recent years, development of a gas discharge light emitting panel, typically a plasma display panel (PDP), has been promoted as an image display device capable of realizing high definition and high brightness. PDPs are easy to increase in screen size and are expected to become more popular in the future.

[0003] In the PDP, a full color image is displayed by the additive color mixture of the three primary colors red, green and blue. In order to perform such image display, the PDP includes a phosphor layer that includes phosphors that emit red, green, and blue colors (red phosphor, green phosphor, or blue phosphor) for each discharge cell. . Each phosphor is excited by irradiation with ultraviolet rays (vacuum ultraviolet rays) generated by gas discharge in the discharge space, and emits light of each color. The discharge cells are arranged in a predetermined pattern, and an image is displayed on the panel by controlling the timing of gas discharge for each discharge cell, that is, the timing of ultraviolet irradiation to the phosphor. The specific structure of the PDP is disclosed in, for example, Hiraki Uchiike and Shigeo Miko, published on May 1, 1997, "All about plasma display", Industrial Research Association, pp79_80, etc. .

[0004] In the PDP, it is known that the light emission characteristics fluctuate with time as the panel is driven in each discharge cell, and many of these fluctuations are caused by ion bombardment or vacuum ultraviolet irradiation during discharge. This is thought to be due to the alteration of the phosphor due to the above. When the phosphor changes in quality, the conversion efficiency for converting ultraviolet light into visible light decreases, and typically the luminance and chromaticity change. Such fluctuations are especially likely to occur when a constant image is displayed like a still image, but the characteristics of the light emitted by the phosphor between the discharge cells with different lighting times (emission characteristics: (For example, brightness and / or chromaticity) is different, so when a pattern different from the above-mentioned fixed pattern is displayed, May occur as an afterimage (generally called “burn-in phenomenon”).

[0005] As the blue phosphor used in the PDP, BAM (BaMgAl 2 O 3: Eu ²⁺ ) is generally used because the luminance and chromaticity during light emission are suitable for an image display device. But BAM

10 17

This causes a decrease in brightness and chromaticity fluctuations caused by driving of the panel, especially a decrease in brightness. For this reason, as a blue phosphor, an attempt has been made to combine BAM and a phosphor having different emission characteristics from BAM.

[0006] For example, Japanese Patent Laid-Open No. 2005-116363 (Reference 1) discloses that a blue phosphor layer is formed from a mixture of two or more types of blue phosphors that are different from each other in both initial luminance and luminance with time. As a specific structure of the blue phosphor layer, a combination of BAM and Ca MgSi 2 O: Eu ²⁺ (CMS) is shown (see Examples). Example

2 6

The initial brightness of the CMS is lower than that of the BAM, but the decrease rate of the brightness of the CMS when the panel is driven for 1000 hours is smaller than that of the BAM. It has been shown that the decrease in luminance of the blue phosphor layer due to panel driving can be suppressed compared to the case where the blue phosphor layer is composed only of BAM.

[0007] Further, for example, JP 2003-313549 A (Document 2) describes, as a blue phosphor having a high luminance after plasma exposure, a phosphor in which part of Ca in CMS is substituted with Sr and BAM. A mixture is shown. In the invention according to Document 2, since the plasma exposure in the example is 15 minutes after the heat treatment for forming the phosphor layer, a technique for increasing the initial luminance of the blue phosphor is considered to be disclosed. It is done.

[0008] Under such circumstances, a gas discharge light-emitting panel is desired in which fluctuations in the light emission characteristics of the phosphor (phosphor layer) due to driving of the panel are reduced and deterioration of the display characteristics of the panel over time is suppressed. .

Disclosure of the invention

[0009] The present inventors have realized such a gas discharge light-emitting panel with a configuration different from that of the conventional technique.

[0010] The gas discharge light-emitting panel of the present invention is disposed on a front plate and a back plate arranged to face each other through a discharge space, and on a main surface of the back plate on the discharge space side, A phosphor layer that emits light by ultraviolet rays generated in the discharge space. Here, the phosphor layer includes first and second phosphors in which the direction of variation of at least one characteristic selected from luminance and chromaticity due to driving of the panel is opposite to each other.

[0011] A gas discharge light-emitting panel according to the present invention as seen from a side different from the above includes a front plate and a back plate arranged so as to face each other through a discharge space, and the discharge space side of the back plate on the discharge space side. A phosphor layer is disposed on the main surface and emits light by ultraviolet rays generated in the discharge space. Here, the phosphor layer is represented by the formula aSr〇 · bEuO · Mg〇 · cSiO

2

The first phosphor includes BaMgAl 2 O 3: Eu ²⁺ as the second phosphor. However, in the above formula

10 17

At first, a, b and d, the following relations are satisfied: 2. 97≤a≤3.5, 0.001≤b≤0.03 and 1.9≤c≤2.

[0012] According to the present invention, it is possible to drive the panel by providing the phosphor layer including phosphors whose directions of variation of at least one characteristic selected from luminance and chromaticity accompanying the driving of the panel are opposite to each other. As a result, fluctuations in the emission characteristics of the phosphor layer can be reduced, and deterioration of the display characteristics of the panel over time can be suppressed.

Brief Description of Drawings

FIG. 1 is a schematic view showing an example of a plasma display panel (PDP) as a gas discharge light-emitting panel of the present invention.

[FIG. 2] FIG. 2 is a schematic view showing an example of luminance variation of a phosphor layer.

FIG. 3 is a schematic diagram showing an example of variation in chromaticity of a phosphor layer.

FIG. 4A is a diagram showing a change in luminance in each phosphor layer sample measured in Example 1.

FIG. 4B is a diagram showing a change in chromaticity in each phosphor layer sample measured in Example 1.

BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following description, the same reference numerals are assigned to the same members, and duplicate descriptions may be omitted.

FIG. 1 shows an example of a plasma display panel (PDP) as a gas discharge light-emitting panel of the present invention. [0016] The PDP 51 shown in FIG. 1 has a pair of substrates (front plate 1 and back plate 2) arranged to face each other with the discharge space 31 therebetween, and a main surface of the back plate 2 on the discharge space 31 side. And a phosphor layer 3 disposed thereon. The phosphor layer 3 includes first and second phosphors as phosphors that emit light by ultraviolet rays generated in the discharge space 31. The first and second phosphors have opposite directions of variation in at least one characteristic selected from luminance and chromaticity when the panel is driven (with light emission). In such a PDP51, the emission characteristics of the first and second phosphors fluctuate in directions opposite to each other by driving the panel. Therefore, fluctuations in the emission characteristics of the phosphor layer 3 can be reduced, and the display characteristics of the panel can be reduced. Can be prevented. Note that, unless otherwise specified, in this specification, variations in luminance and chromaticity are variations accompanying panel driving (ie, during panel driving). The change in luminance can be indicated by, for example, an increase or decrease in a value (Y / y) described later. The variation in chromaticity can be indicated by, for example, an increase or decrease in the value of chromaticity y described later.

[0017] When the phosphor layer 3 includes first and second phosphors whose luminance fluctuation directions are opposite to each other, in other words, the phosphor layer 3 is a first phosphor whose luminance increases. And the second phosphor whose luminance decreases, the variation in the luminance of the phosphor layer 3 can be suppressed. In this case, it can be said that the direction of the change in the first phosphor is a direction in which the luminance increases.

[0018] Conventionally, phosphors used in gas discharge light-emitting panels such as PDP usually have a tendency to decrease in luminance when the panel is driven, and BAM and CMS, as well as Reference 1 (Special 2005-116363). The same applies to the phosphors disclosed in Japanese Patent Laid-Open No. 2003-313549 and Japanese Patent Laid-Open No. 2003-313549. For this reason, for example, by forming a phosphor layer that includes a conventional phosphor that decreases in luminance as the second phosphor and a phosphor that increases in luminance as the first phosphor, the luminance of the phosphor layer can be reduced. Reduction can be reduced, and the effect is greater than in the case of combining phosphors whose luminance decreases as in References 1 and 2.

[0019] A gas discharge light-emitting panel that performs full-color display includes three types of phosphor layers each including blue, green, and red phosphors as phosphor layers. Among them, blue phosphors (blue phosphors) Layer) tends to have a large decrease in luminance. For this reason, the blue phosphor layer has a conventional blue phosphor whose luminance decreases as the second phosphor and a luminance which increases as the first phosphor. In this case, in order to ensure good display characteristics, the first phosphor is preferably also a blue phosphor. That is, in the panel of the present invention, it is preferable that the first and second phosphors are blue phosphors. In this case, the effects of the present invention are particularly remarkable. The blue phosphor means a phosphor having an emission spectrum peak in the wavelength range of 440 to 470 nm, typically in the wavelength range of 450 to 460 nm.

[0020] Examples of phosphors with increased luminance include silicate phosphors such as Sr 2 Si 2 O: Eu and Ba MgSi 2 O: Eu. Since these phosphors are based on Si oxide, the structure is likely to change in the direction of increasing brightness as soon as they are affected by gas and discharge.

[0021] It is preferable to use a phosphor represented by the formula aSrO · bEuO · MgO · cSiO (hereinafter referred to as SMS) as the phosphor whose luminance increases. However, in the above formula, a, b and c satisfy the relations 2.97≤a≤3.5, 0.001≤b≤0.03 and 1.9≤c≤2.1. The ranges of a, b, and c are intended to allow oxygen deficiency or excess in SMS, and the stoichiometric composition in SMS is a + b = 3, c = 2. SMS satisfying the stoichiometric composition can be represented by the formula Sr MgSi 2 O: Eu with Eu as an activator element. It should be noted that phosphors containing a base material and an activator composed of the same elements as SMS exist in the past. Since these conventional phosphors do not have sufficient luminance and chromaticity during light emission, This is not used as a phosphor for gas discharge light emitting panels such as PDP. However, the SMS having the composition represented by the above formula has the luminance and chromaticity satisfying the characteristics required for the phosphor used in the gas discharge light-emitting panel, and the first phosphor of the present invention. It is preferable to use as.

[0022] In SMS, Eu plays a role as an activator, and the divalent Eu ratio (all Eu atoms with different valences) near the surface of the SMS particle (in the range from the surface of the SMS particle to about 10 nm). The atomic fraction of divalent Eu atoms in the inside) is 50. / Les, preferably less than ₀ . By using such an SMS, the luminance and chromaticity at the time of light emission can be made to be more suitable for PDP, and the increase in luminance due to driving of the panel can be further ensured.

[0023] SMS is a blue phosphor having an emission spectrum peak at a wavelength of 460 nm. this Therefore, SMS is preferably included in the blue phosphor layer together with the second phosphor that is a blue phosphor. In other words, it is preferable that the blue phosphor layer contains SMS in the PDP 51. In other words, the blue phosphor layer contains SMS as the first phosphor, and the second phosphor. It is preferable to include a blue phosphor having an emission spectrum peak in the wavelength range of 440 to 470 nm, typically in the wavelength range of 450 to 460 nm.

[0024] For SMSf, one monore MgO, Sr0 2.97-3.5 monole, Eu0 0.001-0.03 monole, Si0 1.9-1. It can be said that it is a phosphor containing mol.

2

[0025] The type of blue phosphor combined with SMS is not particularly limited, but BaMgAl 2 O 3: Eu ²⁺ (BAM) is preferred because of its high luminous efficiency. BAM driving panel

10 17

This is a blue phosphor whose luminance is lowered. Other phosphors combined with SMS include CaMgSi O: Eu Sr MgSi O: Eu (SrBa) MgSi 0: Eu ²⁺

2 4 3 2 8 3 2 8

It is done. These phosphors are blue phosphors, and tend to decrease in luminance when the panel is driven.

[0026] When the phosphor layer 3 contains SMS as the first phosphor and BAM as the second phosphor, the content ratio of the two is not particularly limited. For example, the volume ratio BAM: SMS = 25: 75-75: If it is around 25.

[0027] FIG. 2 shows an example of a variation in luminance in the phosphor layer 3 containing the second phosphor whose luminance is lowered by driving the panel and SMS. In the example shown in FIG. 2, the brightness of the SMS tends to increase according to the panel driving time as shown in (a), and the brightness of the second phosphor as shown in (b). The tendency which falls according to the drive time of a panel is shown. When the phosphor layer 3 includes both phosphors, as shown in (c), it is possible to reduce fluctuations in luminance as compared with the case where only the second phosphor is included. Note that the luminance in Fig. 2 indicates the irradiance value Y in the XYZ color system stipulated by the International Commission on Illumination (CIE) and the chromaticity based on the color system in order to offset the change in chromaticity by driving the panel. The value (YZy) divided by the chromaticity y at the coordinates (x, y).

[0028] The first phosphor is not particularly limited as long as it is a phosphor whose luminance is increased by driving the panel. However, in order to more reliably suppress fluctuations in luminance of the phosphor layer, the first phosphor is not limited. It is preferable that the increase rate of the luminance of the body is a predetermined value or more. Specifically, the above value (Y / y) is Further, it is preferable to increase 3% or more per 1000 hours of panel driving, more preferably 8% or more, and more preferably 10% or more. As will be described later in the Examples, SMS satisfies this increase rate depending on its composition, the above-mentioned divalent Eu ratio, or production conditions.

[0029] The luminance of the first and second phosphors does not always change in opposite directions due to the driving of the panel, that is, the period during which the panel is driven (ie, the first and second phosphors themselves). In at least a part of the period during which light is emitted, it is only necessary to change in directions opposite to each other.

[0030] In conventional phosphors such as BAM and CMS, the luminance always decreases during the panel drive period (the phosphor itself emits light). For this reason, when these conventional phosphors are used as the second phosphor, the luminance of the first phosphor does not necessarily increase due to the driving of the panel. Should be increased during the period. For example, the luminance increase rate described above can be achieved by applying a phosphor layer on the main surface of the back plate by techniques such as coating and baking, and driving the panel for aging for 1000 hours or after aging. The rate of increase over a period of 1000 hours from the start of driving the panel for normal image display is sufficient.

[0031] When the phosphor layer 3 includes first and second phosphors whose chromaticity fluctuation directions are opposite to each other, for example, the phosphor layer 3 increases the chromaticity y by driving the panel. When the phosphor and the phosphor whose chromaticity y is lowered are included, fluctuations in the chromaticity of the phosphor layer 3 can be suppressed. Here, “chromaticity y” means chromaticity y in chromaticity coordinates (x, y) based on the XYZ color system defined by the International Commission on Illumination (CIE). The “chromaticity variation” is not limited to the exemplified variation of chromaticity y, and at least one chromaticity variation selected from chromaticity x and chromaticity y in the chromaticity coordinates (x, y) above. Narare.

[0032] Conventionally, blue phosphors used in gas discharge light-emitting panels such as PDP usually show a tendency that the chromaticity y increases by driving the panel, including BAM and CMS, and References 1 and 2 This also applies to the phosphor disclosed in the above. For this reason, for example, by forming a phosphor layer including a conventional phosphor having an increased chromaticity y as the second phosphor and a phosphor having a decreased chromaticity y as the first phosphor, the phosphor The fluctuation of the chromaticity y of the layer can be suppressed. [0033] Examples of blue phosphors with decreased chromaticity y include silicate phosphors such as Sr 2 Si 2 O: Eu and Ba MgSi 2 O: Eu. Since these phosphors are made of Si oxide, the structure is easily affected by the effects of gas and discharge, and the structure is likely to change in the direction of increasing chromaticity y.

[0034] It is preferable to use the SMS as a phosphor that reduces the chromaticity y. As described above, conventional blue phosphors used in gas discharge light emitting panels such as PDPs usually show a tendency that the chromaticity y increases by driving the panel. Therefore, for example, by using a phosphor layer including a conventional blue phosphor in which chromaticity y increases and SMS in which chromaticity y decreases, variation in chromaticity in the blue phosphor layer can be reduced. As described above, it is preferable that the blue phosphor layer contains SMS from the viewpoint of reducing variation in chromaticity.

[0035] The type of blue phosphor combined with SMS is not particularly limited, but BAM is preferred because of its high luminous efficiency. BAM is a blue phosphor whose chromaticity y increases as the panel is driven. Other examples of the phosphor to be combined with SMS, as a blue phosphor, CaMgSi_〇: Eu ^2+, Sr ^{MgSi_〇: Eu 2+, (SrBa) MgSi} O: such as Eu ²⁺ is like et be. These phosphors show a tendency that the chromaticity y increases as the panel is driven.

FIG. 3 shows an example of variation in chromaticity y in the phosphor layer 3 including the second phosphor whose chromaticity y increases by driving the panel and SMS. In the example shown in FIG. 3, the chromaticity y of SMS tends to decrease with the panel driving time as shown in (a), and the chromaticity y of the second phosphor is in (b). As shown, it tends to increase according to the driving time of the panel. When the phosphor layer 3 contains both phosphors, as shown in (c), the variation in the chromaticity y can be reduced compared to the case where only the second phosphor is contained.

[0037] The chromaticity y in the first and second phosphors does not always have to fluctuate in opposite directions due to the driving of the panel. If it fluctuates in a direction opposite to each other.

The phosphor layer 3 may contain one or more kinds of phosphors (third phosphor) other than the first and second phosphors. The direction of variation of the at least one characteristic in the third phosphor is not particularly limited. For example, it may be the same as the direction of variation of the first phosphor, or the second phosphor. In the same direction as the above May be.

[0039] The content ratios of the first and second phosphors in the phosphor layer 3 are not particularly limited, and are arbitrarily set according to the type of phosphors contained or the light emission characteristics required for the phosphor layer 3. Just do it. The content rate of the 1st fluorescent substance in the fluorescent substance layer 3 is the range of 25-75 volume%, for example.

[0040] The first and second phosphors may change so that both the luminance and chromaticity of the first and second phosphors are in conflict with each other.

[0041] In the PDP 51, all the phosphor layers 3 may not include the first and second phosphors. For example, only the blue phosphor layer may contain the first and second phosphors, and it is located in the image display region of the panel, particularly in the region where the variation in luminance and / or chromaticity is large. Only the phosphor layer 3 may include the first and second phosphors.

[0042] The structure and configuration of each member in the PDP 51, and the material used for each member are not particularly limited as long as the phosphor layer 3 includes the first and second phosphors. If it's a configuration,

In the PDP 51 shown in FIG. 1, the display electrode 13 including the sustain electrode 11 and the scan electrode 12, the dielectric layer 14, and the dielectric layer 14 are generated in the discharge space 31 on the main surface of the front plate 1. A protective layer 15 is provided to protect against plasma. On the main surface of the back plate 2, an address electrode 23, a dielectric layer 22 that protects the address electrode from the plasma, and a partition wall 21 are disposed. The PDP 51 is an AC type PDP having a so-called three-electrode structure. In FIG. 1, the number of electrodes and partition walls in an actual PDP is omitted.

[0044] The material used for the front plate 1 is not particularly limited as long as it has translucency. For example, a glass substrate may be used. The material used for the back plate 2 is not particularly limited. For example, a substrate containing glass and Z or metal may be used. Usually, glass substrates are used for the front plate 1 and the back plate 2.

On the front plate 1, stripe-shaped sustain electrodes 11 and scanning electrodes 12 are arranged in parallel to each other as display electrodes 13.

[0046] Sustain electrode 11 and staggered electrode 12 are transparent electrode (sustain electrode) 11a and transparent electrode (scan electrode) 12a, bus electrode (sustain electrode) l ib and bus electrode (scan electrode) 12 respectively. b is laminated. For the transparent electrodes 11a and 12a, ITO (Indium Tin Oxide), tin oxide or the like may be used. The bus electrodes l ib and 12b may be made of aluminum, copper, silver, a laminate of chromium and copper, or the like. Although not shown, a black film made of glass and black pigment, which is called a black stripe, is provided between the sustain electrode 11 and the scanning electrode 12 to improve the black display quality and increase the contrast of the image. ing. Each electrode and the black film included in the display electrode 13 can be formed on the main surface of the front plate 1 by a method such as screen printing, for example.

[0047] A dielectric layer 14 is disposed on the front plate 1 so as to cover the display electrodes 13. On the dielectric layer 14 (on the discharge space 31 side of the dielectric layer 14), a protective layer is provided. 15 are arranged. The dielectric layer 14 serves as a capacitor for accumulating charges when the PDP 51 displays an image. The dielectric layer 14 may be made of a general material as a PDP, for example, a layer made of low melting point glass mainly composed of lead oxide (PbO), bismuth oxide (BiO), phosphorus oxide (PO), or the like. If it is. The dielectric layer 14 is obtained by applying a dielectric paste obtained by kneading a low-melting glass, a resin, and a solvent by a technique such as printing (for example, screen printing or die coat printing) or transfer (for example, film laminating). It can be formed by coating on the face plate 1, drying and firing.

[0048] A common material for the PDP may be used for the protective layer 15, for example, a layer made of MgO. The protective layer 15 can be formed on the dielectric layer 14 by an electron beam evaporation method, an ion plating method, or a sputtering method.

On the back plate 2, a dielectric layer 22, stripe-shaped partition walls 21 and stripe-shaped address electrodes 23 are arranged. The dielectric layer 22 is disposed so as to cover the address electrodes 23, and the partition walls 21 are disposed so as to be parallel to each other. The phosphor layer 3 is disposed between the adjacent barrier ribs 21, and the region surrounded by the intersection of the address electrode 23 and the display electrode 13 in the discharge space 31 and divided by the barrier rib 21 is the discharge cell. Become. The configuration of the address electrode 23 may be the same as, for example, the configuration of the bus electrode described above. The dielectric layer 22 may be the same as the dielectric layer 14. The partition wall 21 may be formed using glass, pigment, or the like.

[0050] The phosphor layer 3 including the first and second phosphors is the same as the conventional phosphor layer in the PDP. The first and second fluorescence can be formed in an organic solvent such as terpineol containing ethyl cellulose and z or nitrocellulose at a concentration of 5% to 10% by weight, for example. The paste obtained by dispersing the body can be formed by applying between the partition walls 21 by screen printing or line jet method and baking it in the range of 450 ° C to 550 ° C. When the first and second phosphors are dispersed in the organic solvent, the mixture of the first and second phosphors may be dispersed, or each phosphor is individually injected into the organic solvent. You may make it disperse | distribute.

[0051] The front plate 1 and the back plate 2 are arranged so that the protective layer 15 and the partition wall 21 face the discharge space 31, and the striped display electrodes 13 and address electrodes 23 are formed on the front plate 1 and the back plate 2. They are arranged facing each other so as to be orthogonal when viewed from the main surface. Sealing members made of low-melting glass are disposed on the peripheral portions of the front plate 1 and the back plate 2 to keep the discharge space 31 hermetic. The discharge space 31 is filled with a discharge gas containing a rare gas such as neon or xenon. The pressure of the discharge gas in the discharge space 31 is, for example, in the range of 53 kPa to 79 kPa (400 Torr to 600 Torr).

[0052] In the PDP 51, a video signal voltage is selectively applied to the display electrode 13 to excite the phosphor contained in the phosphor layer 3, and the excited phosphor emits red, green, or blue light. Can display color images.

[0053] As a method for manufacturing PDP 51, a general method may be used as a method for manufacturing PDP.

The gas discharge light-emitting panel of the present invention is not limited to the PDP as shown in FIG. 1, but irradiates phosphors with ultraviolet rays (particularly, vacuum ultraviolet rays having a wavelength of 200 nm or less) generated by gas discharge. As long as it is a light-emitting panel using light emitted from the phosphor, there is no particular limitation. Among such light-emitting panels, in addition to PDPs, LCD panel backlights, character display displays, lighting panels, etc., the fluctuations in chromaticity and brightness are significant in the display characteristics of the panel. When the present invention is applied to an influencing PDP, the effect obtained is great.

Example

Hereinafter, the present invention will be described in more detail with reference to examples. The present invention is not limited to the following examples. [0056] (Example 1)

In Example 1, a PDP provided with a phosphor layer A containing SMS and BAM, a phosphor layer B made of BAM, and a phosphor layer C made of SMS was produced, and a lighting test was performed on the produced PDP. Then, the variation of the light emission characteristics of each phosphor layer accompanying the driving of the panel was evaluated. The SMS composition was a = 3, b = 0.005, and c = 2.

[0057] First, E chill cellulose-containing (50 weight ^_0/0) a one Tabineoru dispersion solvent, the paste was formed by dispersing S MS and / or BAM, the formed paste, screen printing or line It apply | coated to the board | substrate which consists of glass with the jet method, and the whole was baked in the range of 450 to 550 degreeC, and produced fluorescent substance layer AC. Phosphor layer A consists of phosphor layer A-1 with an SMS volume fraction of 25% for all phosphors in the phosphor layer, and phosphor layer A with an SMS volume fraction of 70% by volume. — Two types, 2 and 2, were made.

Next, a PDP 51 as shown in FIG. 1 was produced using each of the produced phosphor layers. PDP51 was produced according to a general PDP production method. When manufacturing PDP51, all phosphor layers A to C were placed in one panel in order to prevent variations in emission characteristics due to differences in the atmosphere in the discharge space.

[0059] Next, the PDP 51 manufactured in this way is connected to a general PDP drive device and continuously lit, and the luminance (Y / y) and chromaticity y in each phosphor layer are changed over time. The measurement was performed using a CRT color analyzer (manufactured by Konica Minolta: CA_100plus). The PDP area for measuring changes in luminance and chromaticity was continuously lit and displayed in white, and the luminance was evaluated as a relative value of emission intensity with an initial value of 100%. The continuous lighting time was 2500 hours, and the AC voltage applied to the discharge space for lighting the panel was 175 V.

[0060] The measurement results are shown in FIG. As shown in Fig. 4 (a), the brightness of phosphor layer B made of BAM was lowered by driving the panel, and the brightness of phosphor layer C made of SMS was increased by driving the panel. On the other hand, the phosphor layer A-1 containing 25% by volume of SMS and 75% by volume of BAM as the phosphor, compared to the phosphor layer B, was able to reduce fluctuations in brightness due to panel driving.

[0061] On the other hand, as shown in FIG. 4 (b), the phosphor layer B made of BAM is driven by driving the panel. The chromaticity y increases (in Fig. 4 (b), the fluctuation of the chromaticity y is indicated by the amount of fluctuation (A y) from the initial value). The chromaticity y decreased. On the other hand, in the phosphor layer A-2 containing 70% by volume of SMS and 30% by volume of BAM as the phosphor, fluctuations in chromaticity y due to panel driving can be reduced compared to phosphor layer B.

[Example 2]

In Example 2, a plurality of SMS phosphor samples in which the content of Eu as an activation element was changed were prepared, and the change in luminance was evaluated as the light emission characteristics.

[0063] SrCO, EuO, MgO and SiO were used as starting materials, and these were weighed so as to have a predetermined composition and wet-mixed in pure water using a ball mill. Next, the formed mixture

After drying at 150 ° C for 10 hours, firing in air at 1100 ° C for 4 hours, and further in a mixed gas of nitrogen, hydrogen and oxygen from 1100 ~: firing at 1300 ° C for 4 hours to phosphor (SMS ) Here, the divalent Eu ratio near the surface of the phosphor particles was set to 50% or less by precisely controlling the oxygen partial pressure in the mixed gas. The divalent Eu ratio was determined from the intensity ratio (peak area ratio) between the peak attributed to divalent Eu and the peak attributed to trivalent Eu by XPS (X-ray photoelectron spectrometer).

[0064] The composition of the SMS sample prepared in Example 2 is shown in Table 1 as values of a, b, and c. In Example 2, eight sample samples (samples 1 to 8) in which the value of b corresponding to the Eu content is in the range of 0.001 to 0.03, and the value of b is 0.1. One type of comparative sample (Sample A) was prepared.

[0065] For each sample produced in this way, (1) the brightness in the powder state as produced, (2) a phosphor paste formed by mixing with an organic solvent was applied between the barrier ribs on the back plate. And brightness when fired at 500 ° C to form a phosphor layer, (3) the PDP panel was assembled in the same manner as in Example 1, and the brightness when 10 hours passed after the panel was started, and (4) Time point force in (3) above The brightness when the panel was driven for 1000 hours was evaluated. (1) and (2) were evaluated by irradiating the phosphor in the state of the phosphor layer formed on the powder or the back plate with ultraviolet light having a wavelength of 145 nm, and (3) and (4) were evaluated in Example 1. It was evaluated in the same way. Note that 10 hours in (3) corresponds to the time when the aging process is generally completed in the PDP manufacturing process. [0066] Table 1 below shows the evaluation results. As a conventional example, evaluation results for both phosphors of BAM and CMS (CaMgSi ○: Eu ²⁺ ) are also shown. In addition, the brightness of each sample is evaluated by the above-mentioned value (Y / y) and expressed as a relative value where the brightness in the powder state of BAM is 100.

[0067] [Table 1]

Relative value with the value at the time of BAM (1) as 100

[0068] As shown in Table 1, in BAM and CMS, which are conventional blue phosphors, (1) the brightness in the powder state is the highest (2) during the formation of the phosphor layer, (3) the panel drive starting force is also After 10 hours, and (4) after a further 1000 hours of panel operation, the brightness continued to decrease. Comparing the results of time points (3) and (4), it was found that 1000 hours of panel driving resulted in a brightness reduction of about 10% for BAM and about 9.4% for CMS.

[0069] On the other hand, in Samples:! To 8, although the luminance was once greatly reduced by the formation of the phosphor layer, the luminance was increased by driving the panel. Comparing the results of time points (3) and (4), as shown in Table 1, approximately 1.5% for sample 1 and approximately 3.8% for sample 2 after 1000 hours of panel operation. 3 is about 4.2% , Ί or 13.6 ^_0/0 in Sanpunore 4, ί or about 8. Ί in Sanpunore 5. Ί Maitoshaku 11.1 ^_0/0 Sanpunore 6, about 8.4% in the service Npunore 7, in Sample 8 of about 3. increase of 3% luminance occurs in.

[0070] As in Samples:! To 8, a phosphor that shows a tendency for luminance to increase by driving the panel after the luminance has once decreased due to the formation of the phosphor layer has not been known. In Samples 1-8, the reason for such luminance fluctuation is not clear, but it can be recovered by the thermal degradation power S of the SMS generated by the heat treatment during the formation of the phosphor layer and the driving atmosphere of the panel. It may be the cause.

[Example 3]

In Example 3, the change in chromaticity y was evaluated as the light emission characteristics of the SMS phosphor sample prepared in Example 2.

[0072] Specifically, with respect to the example samples prepared in Example 2:! To 8 and Comparative Sample A, (1) the chromaticity y in the powdered state as prepared, (2) the organic solvent and The phosphor paste formed by mixing is applied between the barrier ribs on the back plate and baked at 500 ° C to form a phosphor layer. (3) Similar to Example 1, PDP panel Assessed were chromaticity y when assembly and panel driving started 10 hours later, and (4) chromaticity y when panel driving continued for 1000 hours from point (3) above. (1) and (2) are evaluated by irradiating the phosphor in the state of the phosphor layer formed on the powder or the back plate with ultraviolet light having a wavelength of 145 nm, and (3) and (4) are performed. Evaluation was performed in the same manner as in Example 1. As described above, the 10 hours in (3) corresponds to the time when the aging process is generally completed in the PDP manufacturing process.

[0073] Table 2 below shows the evaluation results. As a conventional example, BAM and CMS (CaMgSi

(Circle): The evaluation result with respect to both fluorescent substance of Eu <^2+> ) is also shown collectively.

[0074] [Table 2] SMS Female Bivalent 1000 hours sample

E u rate Λ ': According to Ε¾

No. a b c (1) (2) (3) (4)

(%) Change in chromaticity y

1 2.97 0.03 2 50 0.0652 0.0680 0.0752 0.0751 -0.0001

2 3.5 0.001 2 30 0.0503 0.0527 0.0590 0.0570 -0.0020

3 3.1 0.003 2 10 0.0559 0.0582 0.0644 0.0640 -0.0004

4 3 0.006 2 5 0.0551 0.0573 0.0628 0.0623 -0.0005

5 3 0.005 2 5 0.0549 0.0574 0.0617 0.0613 -0.0004

6 3 0.004 2 5 0.0550 0.0576 0.0632 0.0627 -0.0005

7 3 0.003 2 5 0.0534 0.0558 0.0602 0.0598 -0.0004

8 3 0.002 2 5 0.0531 0.0557 0.0600 0.0580 -Ό.0020

A

2.9 0.1 2 80 0.1200 0.1227 0.1352 0.1355 0.0003 itmi

BAM ― One ― ― 0.0554 0.0604 0.0643 0.0657 0.0014

CMS ― ― ― ― 0.0502 0.0530 0.0575 0.0578 0.0003

[0075] As shown in Table 2, with BAM and CMS, which are conventional blue phosphors, (1) the chromaticity y in the powder state is the smallest (2) when forming the phosphor layer, (3) panel drive The value continued to increase in the order of 10 hours after the starting force and (4) after another 1000 hours of panel operation. Comparing the results of (3) and (4), it was found that 1000 hours of panel drive resulted in an increase in chromaticity y of 0.0014 for BAM and 0.0003 for CMS.

[0076] On the other hand, it was found that the chromaticity y in Samples 1 to 8 increased once due to the formation of the phosphor layer and the aging treatment, but conversely decreased due to subsequent panel driving.

[0077] As in Samples:! To 8, a phosphor that shows a tendency that the chromaticity y tends to decrease by driving the panel after the chromaticity y increases due to the formation of the phosphor layer has not been known. In Samples:! ~ 8, the reason for this variation in chromaticity y is not clear, but the thermal degradation of SMS caused by the heat treatment during phosphor layer formation is the same as the change in luminance described above. It may be caused by recovery by the driving atmosphere.

Industrial applicability

[0078] According to the present invention, the directions of fluctuations in the light emission characteristics accompanying the driving of the panel are opposite to each other. By providing the phosphor layer containing the phosphor, it is possible to provide a gas discharge light-emitting panel in which the deterioration of display characteristics is suppressed.

Claims

The scope of the claims

[1] a front plate and a back plate arranged to face each other through a discharge space;

A gas discharge light-emitting panel that is disposed on a main surface of the back plate on the discharge space side and emits light by ultraviolet rays generated in the discharge space; A gas discharge light emitting panel comprising first and second phosphors in which the direction of variation of at least one characteristic selected from luminance and chromaticity accompanying driving is opposite to each other.

[2] The direction of the variation in the first phosphor is a direction in which luminance increases.

The gas discharge light emitting panel according to 1.

[3] The first phosphor is a phosphor represented by the formula aSr〇 · bEuO · Mg〇 · cSiO

2

The gas discharge light-emitting panel according to claim 2.

However, in the above formula, a, b and c satisfy the following relationship.

2. 97≤a≤3.5

0. 001≤b≤0. 03

1. 9≤c≤2. 1

[4] Expressed by the value (YZy) obtained by dividing the stimulus value Y in the XYZ color system defined by the International Commission on Illumination (CIE) by the chromaticity y in the chromaticity coordinates (x, y) based on the color system. The gas discharge light-emitting panel according to claim 2, wherein the luminance power of the first phosphor is increased by 3% or more per 1000 hours.

[5] The gas discharge luminescence according to claim 2, wherein the second phosphor is BaMgAl 2 O 3: Eu ⁺

10 17

panel.

[6] The direction of the variation in the first phosphor is a direction in which the chromaticity y in the chromaticity coordinates (x, y) based on the XYZ color system defined by the International Commission on Illumination (CIE) decreases. The gas discharge light-emitting panel according to claim 1.

[7] The first phosphor is a phosphor represented by the formula aSr〇 · bEuO · Mg〇 · cSiO

2

The gas discharge light-emitting panel according to claim 6.

However, in the above formula, a, b and c satisfy the following relationship.

2. 97≤a≤3.5

0. 001≤b≤0. 03

1. 9≤c≤2. 1

[8] The gas discharge luminescence according to claim 6, wherein the second phosphor is BaMgAl 2 O 3: Eu ⁺

10 17

panel.

9. The gas discharge light-emitting panel according to claim 1, wherein the first and second phosphors are blue phosphors having emission spectrum peaks in a wavelength range of 440 to 470 nm.

10. The gas discharge light-emitting panel according to claim 1, which is a plasma display panel.

[11] a front plate and a back plate arranged to face each other through the discharge space;

A gas discharge light-emitting panel disposed on a main surface of the back plate on the discharge space side and emitting light by ultraviolet rays generated in the discharge space, wherein the phosphor layer has the formula aSrO a first phosphor represented by bEuO · MgO · cSiO;

2

A gas discharge light-emitting panel comprising BaMgAl 2 O 3: Eu ²⁺ as the second phosphor.

10 17

However, in the above formula, a, b and c satisfy the following relationship.

2. 97≤a≤3.5

0. 001≤b≤0. 03

1. 9≤c≤2. 1

[12] Expressed by the value (YZy) obtained by dividing the stimulus value Y in the XYZ color system defined by the International Commission on Illumination (CIE) by the chromaticity y in the chromaticity coordinates (x, y) based on the color system. 12. The gas discharge light-emitting panel according to claim 11, wherein the brightness of the first phosphor is increased by 3% or more per 1000 hours of panel driving.

13. The gas discharge light-emitting panel according to claim 11, which is a plasma display panel.